Traditionally, subsea hydrocarbon production control systems have relied upon low data rate, wire-based telemetry for communication via umbilicals connecting the surface and subsea facilities. This well-proven technology has been more than adequate for the modest update rates historically required. The use of “communications on power” (COP) offered a useful cost saving for the umbilicals.
Recently, the advent of more demanding control and instrumentation requirements for production optimisation, intelligent well systems and subsea processing has led to requirements for higher data rates—sometimes in combination with very long distance transmission.
Optical telemetry combines very high data rates over long offsets with complete noise immunity from high voltage power transmission. However, the cost is high and cannot always be justified for intermediate requirements.
Recent technical advances now permit a robust, COP, wire-based solution with a much higher data rate (115 kbits/sec) over offset distances of typically 50 km.